Hello,

I have an 89 Suburban 454 3/4 ton (owned for decades) and it runs very well. In the last week, the heat / defrost stopped generating cabin heat when directed at the wind shield. Today was a cold morning and after driving and parking mist came out of the cabin heater vents (and I think the mist is very light coolant mist, not water moisture mist). I also smell light coolant when driving and the windows are rolled up. So, looking around the vehicle, I found coolant dripping mildly onto the ground, somewhere between the engine and the firewall on the front passenger side about 1 foot toward the interior relative to the external body.

So, it seems the heat loss and the light coolant mist coming from the cabin heater vent are related. I have my own theory, but if I present the symptoms then someone might shed some light on what they think this description (sickness) means. Yes, I checked the oil dip stick and I do not see any bubbles in the oil and the oil is 6 weeks old, clean and looks as I expect it to.

Thanks for any insights,
Steve

 

if coolant is misting the windshield; you need a new heater core.

 

Thank you